Thread-controlling mechanism for wax-thread leather-sewing machines.



v G. A. & s A. DOBYNE. THREAD CONTROLLING MECHANISM FOR WAX THREAD LEATHER SEWING MACHINES. APPLICATION FILED DEC. 6. I9I2.'

1 985273 Patented Sept. 19, 1916.

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(LA. & s. A. DOBYNE. J THREAD CONTROLLING MECHANISMFOR WAX THREAD LEATHER SEWING MACHINES.

APPLICATION FILED DEC. 6,1912. 1,198,627.

Patented Sept. 19, 1916.

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I Gemyeilflgne. d "gay- Y G. A. & S. A DOBYNE.

THREAD CONTROLLING MECHANiSM FOR WAX THREAD LEATHER'SEWING MACHINES.

APPLICATION FILED DEC.6.1912.

1,198,627. Patented 19,1916.

3 SHE -SHEET 3.

UNITED STATES PATENT OFFICE.

GEORGE A. DOBYNE AND STEPHEN A. DOBYNE, OF ST. LOUIS, MISSOURI, ASSIGNORS 'IO CHAMPION SHOE MACHINERY COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

THREAD-CONTROLLING MECHANISM FOR WAX-THREAD LEATHER-SEWING MACHINES.

Application filed December 6, 1912.

To all whom it may concern Be it known that we, GEORGE A. DOBYNE and STEPHEN A. DOBYNE, both citizens of the United States, and residing at St. Louis, in the State of Missouri, have invented certain new and useful Improvements in Thread- Controlling Mechanism for Wax-Thread Leather-Sewing Machines, of which the following is a specification.

This invention relates to wax thread leather sewing machines and more particularly to thread controlling mechanism there for.

There are at present two general types of thread controlling mechanisms. One of these types is provided with a thread-lock or clamp for locking or holding the thread against movement while the stitch is being set; it is therefore necessary to provide means for accurately measuring the thread required for forming the stitches. The other type is provided with a slip tension device, and the take-up takes up and sets the stitch against the yielding tension of this device. After the stitch is set the take-up operates to draw the thread for the next stitch through the slip tension device, the thread being drawn by the surplus movement of the take-up. The thread measuring means of the first type is complicated and must be extremely accurate so as to accurately measure th thread according to the thickness of the work, and this type does not take care of all the conditions encountered in sewing material such as a shoe sole, where the length of the stitch must vary. On the other hand the type employing a slip tension is open to the objection that the take-up is liable to steal thread from the supply and through the tension so that the required accuracy is not obtained.

In wax thread leather sewing machines, more especially those of the lock-stitch type, a large loop of waxed thread is drawn back and forth through the work. The take-up must therefore have a long stroke, and in high speed machines this take-up must op erate at a high linear speed. When the loop of the needle thread, after passing over the Specification of Letters Patent.

Patented Sept. 19, 1916.

Serial No. 735,212.

shuttle, is taken up and set by the take-up there is considerable resistance offeredto the free movement of the waxed thread which resistance must be overcome. The needle thread must be started by the take up, the loop of waxed thread must be drawn down to the face of the work, and this loop must be drawn into the work. Now it has been found that the amount of resistance to be overcome and therefore the amount of pull required to start the waxed needle thread is considerable. It has also been found that when the take-up starts to move back on its take-up stroke the high speed at which this take-up operates in high speed machines is liable to cause a lashing of th thread. These resistances to the free movement of the needle thread are liable to cause the thread to be drawn from the supply and through the slip tension before the stitch is set so that the stitch will be set imperfectly and ununifo-rmly. It is objectionable to make the slip tension too tight as this will cause the thread to cut through the material and is also liable to break the thread.

The objects of this invention therefore are to construct a wax thread controlling mechanism of simple form which will set the stitches uniformly and accurately, and which will prevent the pulling of the waxed needle thread from the supply except when this thread is to be drawn for the next stitch.

Further objects will appear from the detail description taken in connection with the accompanying drawings, in which:

Figure 1 is a front elevation of a machine embodying this invention. Fig. 2 is a side elevation, Fig. 3 is a detail view showing the parts in a different position, Fig. 4; is a view illustrating the operation of the machine, and Fig. 5 is a section on the line 55 Fig. 2.

We have found that if the waxed needle thread is locked or held against movement until after the take-up has started the thread, and until the loop is drawn nearly to the face of the work, that the actual setting of the stitch can be accurately per formed against a yielding tension. In accordance with this invention therefore the thread is locked or held against movement while it is being taken up by the take-up, but is held under a yielding tension while the stitch is being set and while the thread is being drawn for the next stitch. The thread is locked against movement until after the take-up has started to draw the needle thread from the shuttle, and preferably until the needle thread loop is discharged from the shuttle and is drawn nearly to the face of the work. The thread is thereafter unlocked and is only held by a yielding tension, which tension is however of sufficient strength to permit the stitch to be set properly.

Referring to the accompanying drawings which illustrate an outsole sewing machine 9 designates a machine head having amain drive shaft 10 mounted thereon provided with cam wheels 12, 13 and 14. A work support or table 15 is mounted on the head and has cooperating with it a presser-foot 16. The stitch forming mechanism comprising an awl 17, a curved hook needle 18, a looper 19 and a shuttle 20, is of usual construction and may be substantially as shown in Patent No. 473,870, dated April 26, 1892.

The cam wheel 14 is provided with a cam.

groove 11 cooperating with acam roll 21 on an arm 22 mounted on a rock shaft 23, which rock' shaft has an arm 21 connected by a link 25 with the arm 26 of a take-up shaft 27 extending across the machine. The shaft 27 has rigidly mounted thereon a takeup lever 28 provided with the usual thread engaging roll.

A shaft or stud 29 extends laterally from the machine head and has loosely mounted thereon a wheel 30 provided with V-shaped grooves 31 and 32. A washer or plate 33 on the shaft is held against the wheel 30 by means of a spring 3 1- mounted on the shaft, and the tension of this spring can be adjusted by nuts 35. A lever 36 pivoted at 37 on the machine head is provided with a brake shoe 38 adapted to engage the groove 32, and a spring 39 bearing against the lever 36 normally tends to hold the brake shoe in engagement with the wheel 30. A cam lug- 40 on the take-up lever 28 engages with a cam roll 41 on the lever 36 so as to move the shoe 38 out of engagement with the wheel 30. An auxiliary tension device 42 pivoted on the machine head is normally moved in the direction of the arrow by means of a light spring as shown, and the downward movement of this tension device is limited by cooperating lugs 43 and n on the auxiliary tension and the machine head respectively. This auxiliary tension is of well known construction and its function is well forming devices.

known, namely, to take up the slack in the needle thread.

The needle thread passes from a wax pot 100 around the wheel 30 and in the groove 31 therein, over the auxiliary tension, back under the take-up, and then to the stitch During the operation of the machine the cam 14 will through its connections operate to oscillate the take-up shaft 27 and move the take-up lever up and down. \Vhen the take-up lever is up the lug 40 will be out of engagement with the cam roll 41 so that the spring 39 is free to throw the brake shoe 38 into engagement with the wheel 30 and hold or look this wheel and therefore the needle thread wrapped around the wheel against movement. As the take up reaches the lower limit of its take-upstroke the lug LO will engage the cam roll 41 and move the brake shoe out of the groove 32. The wheel 30 will then be unlocked so that the wheel and the thread will be only held frictionally by the washer 33 under the tension of the spring 34. The needle thread will therefore be locked against movement during the first part of the take-up stroke of the take-up lever but will be only yieldingly held against movement during the last part of the take-up stroke.

The mechanism is so constructed and ad justed that the needle thread 51 will be locked against movement until the loop 53 of the needle thread has passed entirely off of the shuttle and is nearly drawn to the face of the work as shown in Figs. 3 and l. In'Fig. 3 the parts are in such a position that the lug 40 is just in engagement with the cam roll 41 and a further downward movement of the takeup lever will cause this lug to move the brake shoe 38 out of the groove After the needle thread is taken up and the loop 53 is drawn nearly down to the work as shown in Figs. 3 and 4 the brake shoe is released so that the needle thread will not be under the yielding tension caused by the spring 34. The take-up will now operate to draw the loop 53 into the work carrying with it the shuttle thread 52 so as to set the stitch against a yielding tension. The take-up will then operate to draw from the supply and through the tension the thread for the next stitch. In Fig. 2 the parts are in position with the take-up at the lower limit of its take-up stroke, with the stitch fully set and the thread for the next stitch drawn from the supply.

During the first part of the take-up strokeof the take-up lever and while the needle take-up performs its function to take-up the thread from the shuttle, the needle thread is positively locked against movement. The lashing of the thread which may be caused by the quick movement of the take-up, and the starting resistance offered by the waxed thread and the work, will therefore not cause the thread to be drawn from the supply. The thread is positively locked against movement when the take-up starts the thread, and this positive lock is maintained until the loop of needle thread has been fully or nearly taken up, whereby the needle thread is positively locked while the long waxed loop of thread is drawn back through the work. lVhen however, the take-up starts to set the stitch the thread will be held only by a yielding tension, and this yielding tension is maintained until the stitch has been fully set. It will be noted that the thread pulling movement of the take-up decreases during its take-up stroke. When the downward speed of the end of the take-up is a maximum, the thread remains locked, while the yielding tension is applied when the downward speed is a minimum. This further avoids lashing of the thread at a time when the brake shoe is released and permits a uniform and accurate setting of the stitch. The yielding tension can be accurately adjusted by operatingthe nuts 35, so as to adapt the machine for different grades of material. This adjustment will not however disturb the operation of the brake shoe.

It will be noted that the thread tension is positioned below *and in close proximity to the take-up. This reduces the length of the thread between the truck or roll on the takeup lever and the tension to a minimum. By controlling the thread tension by a lug on the take-up lever, z. 6., by means interconnected with the take-up, it is insured that this tension will be operated in accurate time relation with respect to the take-up. The spring 34 causes the thread to be under the tension applied by that spring during the entire cycle of operations of the machine, and the thread is held only under this yielding tension when it is released by the looking means. All these features of construction result in a more accurate operation and action of the thread controlling mechanism, and insure that the lock will be set a uniform distance from the face of the work. irrespective of its thickness, and irrespective of the length of the stitches, and other conditions which may be encountered.

It is obvious that various changes may be made in the details of construction without departing from the spirit of this invention, and it is therefore to be understood that this invention is not to be limited to the specific construction shown and described.

Having thus described the invention what is claimed is:

1. In a wax thread sewing machine, the combination with a stitch setting take-up, of a thread tension, and means mounted on and controlled by said take-up for causing said tension to lock the waxed needle thread against movement while the take-up takes up the thread, and for thereafter causing said tension to hold the needle thread under yielding tension while the take-up sets the stitch.

2. In a wax thread sewing machine, the combination with a stitch setting take-up and a shaft therefor, of a thread tension, and means mounted on said take-up shaft for causing said tension to lock the waxed needle thread against movement while the take-up takes up the thread, and for there after causing said tension to hold the needle thread under yielding tension while the take-up sets the stitch.

8. In a wax thread sewing machine, the combination with wax thread stitch-forming mechanism, of mechanism for taking up and setting the stitch, and means controlled by said take-up mechanism for locking the waxed needle thread while the stitch is being taken up, and for thereafter holding the needle thread under yielding tension while the stitch is being set.

4. In a wax thread sewing machine, the combination with a stitch-setting take-up, of a yielding thread tension, a brake operating to brake said tension while the take-up takes up the waxed needle thread, and means operated by said take-up for operating said brake to release the tension while the takeup sets the stitch.

5. In a sewing machine, the combination of a stitch setting take-up member having a thread engaging part, a thread tension separate from said take-up member, means for operating said take-up member to cause said take-up member to take up and set the stitch, and means operating through said take-up member to actuate said thread tension near the end of the take up stroke of said take-up member to relieve the tension on the thread while the stitch is being set.

6. In a sewing machine, the combination of a stitch setting take-up lever having a thread engaging part, a thread tension, and a lug on said take-up lever adapted to engage and actuate said tension near the end of the take up stroke of said take-up member to relieve the tension on the thread while the stitch is being set.

7. In a wax thread leather sewing machine, the combination with a relatively short stitch setting take-up the thread pulling action of which decreases during its take-up stroke, of means for locking the needle thread during the first part of the take-up stroke of the take-up, and for thereafter holding the thread under yielding tension during the last part of the take-up stroke.

8. In a wax thread, lock-stitch, leather sewing machine, the combination with wax thread stitch-forming mechanism, including a hooked needle, and wax applying means for the needle thread, of means for machine and when the needle thread is re- 10 taking up and setting the stitch, and means leased by said locking means.

for locking the wa-Xed needle thread while In testimony whereof we afiix our signathe stitch is being taken up, and for theretures in presence of two witnesses.

after holding the needle thread under yield- GEORGE A. DOBYNE. ing tension While the stitch is being set, said STEPHEN A. DOBYNE. last means operating to hold the needle lVitnesses:

thread under such yielding tension at all L. F. MAHLER,

times during the cycle of operations of the J. H. BRUNINGA.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

